Stones Flashcards
Vignette: A 45-year-old man presents with recurrent kidney stones. On further evaluation, you suspect primary hyperparathyroidism as the underlying cause.
Options:
A) 2–5%
B) 3–5%
C) 10–40%
D) 20–40%
Correct Answer: B) 3–5%
Explanation:
A) 2–5%: Incorrect, the prevalence of Resorptive hypercalciuria due to primary hyperparathyroidism is 3–5%.
B) 3–5%: Correct, Resorptive hypercalciuria, often linked to primary hyperparathyroidism, has a prevalence of 3–5%.
C) 10–40%: Incorrect, this prevalence rate is for Hyperuricosuric calcium nephrolithiasis and Hypocitraturic calcium nephrolithiasis.
D) 20–40%: Incorrect, this prevalence rate corresponds to Absorptive hypercalciuria.
Memory Tool: Think “Resorp-three-five” to remember the prevalence of Resorptive hypercalciuria.
Reference Citation: Modified from Pearle MS, Pak CY, in “International yearbook of nephrology,” 1996, Table 91.2, paragraph 1.
Rationale: Knowing the prevalence of different types can help guide diagnostic evaluations.
Topic: Metabolic/Environmental defect causing Renal Hypercalciuria
Vignette: A 37-year-old woman experiences her third episode of renal stones within a year. A metabolic evaluation indicates impaired renal calcium reabsorption.
Options:
A) Absorptive hypercalciuria
B) Renal hypercalciuria
C) Renal phosphate leak
D) Hyperuricosuric calcium nephrolithiasis
Correct Answer: B) Renal hypercalciuria
Explanation:
A) Absorptive hypercalciuria: Incorrect, this condition is due to increased gastrointestinal calcium absorption.
B) Renal hypercalciuria: Correct, impaired renal calcium reabsorption leads to Renal hypercalciuria.
C) Renal phosphate leak: Incorrect, this is characterized by impaired renal phosphorus absorption.
D) Hyperuricosuric calcium nephrolithiasis: Incorrect, this is due to dietary purine excess or uric acid overproduction.
Memory Tool: “Hyper-calciu-‘Renal’-ya” to remember that renal calcium problems relate to Renal hypercalciuria.
Reference Citation: Modified from Pearle MS, Pak CY, in “International yearbook of nephrology,” 1996, Table 91.2, paragraph 1.
Rationale: Understanding the metabolic cause can inform targeted treatment.
Topic: Prevalence of Cystinuria in Nephrolithiasis
Vignette: A 24-year-old man presents with painful renal colic. You diagnose him with Cystinuria.
Options:
A) <1%
B) 5–10%
C) 15–30%
D) 20–40%
Correct Answer: A) <1%
Explanation:
A) <1%: Correct, Cystinuria is a rare cause of nephrolithiasis, with a prevalence of less than 1%.
B) 5–10%: Incorrect, this prevalence range is for Hypomagnesiuric calcium nephrolithiasis.
C) 15–30%: Incorrect, this corresponds to Idiopathic low urine pH.
D) 20–40%: Incorrect, this is the prevalence of Absorptive hypercalciuria.
Memory Tool: Think “Cysti-nu-ria, <1 rare-ia” to remember its rarity.
Reference Citation: Modified from Pearle MS, Pak CY, in “International yearbook of nephrology,” 1996, Table 91.2, paragraph 1.
Rationale: Recognizing rare causes is crucial for an accurate diagnosis.
opic: Prevalence of Hypomagnesiuric Calcium Nephrolithiasis
Vignette: A 52-year-old woman is experiencing repeated bouts of kidney stones. Her lab results show decreased intestinal magnesium absorption.
Options:
A) 2–15%
B) 3–5%
C) 5–10%
D) 10–50%
Correct Answer: C) 5–10%
Explanation:
A) 2–15%: Incorrect, this is the prevalence range for Hyperoxaluric calcium nephrolithiasis.
B) 3–5%: Incorrect, this corresponds to Resorptive hypercalciuria.
C) 5–10%: Correct, the prevalence of Hypomagnesiuric calcium nephrolithiasis is 5–10%.
D) 10–50%: Incorrect, this prevalence range is for Hypocitraturic calcium nephrolithiasis and Low urine volume.
Memory Tool: Think of “Hypo-magnesiuric, mag-5-10” for easy recall.
Reference Citation: Modified from Pearle MS, Pak CY, in “International yearbook of nephrology,” 1996, Table 91.2, paragraph 1.
Rationale: Knowing the prevalence of a condition aids in diagnosis and management.
Topic: Metabolic/Environmental defect causing Hyperuricosuric Calcium Nephrolithiasis
Vignette: A 60-year-old male has been diagnosed with Hyperuricosuric calcium nephrolithiasis. He is a known meat lover.
Options:
A) Oxalate overproduction
B) Dietary purine excess
C) Impaired renal phosphorus absorption
D) Gastrointestinal alkali loss
Correct Answer: B) Dietary purine excess
Explanation:
A) Oxalate overproduction: Incorrect, this corresponds to Primary hyperoxaluria.
B) Dietary purine excess: Correct, Hyperuricosuric calcium nephrolithiasis often occurs due to dietary purine excess or uric acid overproduction.
C) Impaired renal phosphorus absorption: Incorrect, this leads to Renal phosphate leak.
D) Gastrointestinal alkali loss: Incorrect, this is related to Chronic diarrheal syndrome in Hypocitraturic calcium nephrolithiasis.
Memory Tool: Remember “Hyper-‘uric’-osuric = excess purine” to keep the link in mind.
Reference Citation: Modified from Pearle MS, Pak CY, in “International yearbook of nephrology,” 1996, Table 91.2, paragraph 1.
Rationale: Dietary modification may be key in treating this form of nephrolithiasis.
opic: Prevalence of Low Urine Volume as a Cause of Nephrolithiasis
Vignette: A 38-year-old woman presents with kidney stones. She confesses to consuming very little water daily.
Options:
A) <1%
B) 5–10%
C) 10–50%
D) 15–30%
orrect Answer: C) 10–50%
Explanation:
A) <1%: Incorrect, this is the prevalence of Cystinuria.
B) 5–10%: Incorrect, this corresponds to Hypomagnesiuric calcium nephrolithiasis.
C) 10–50%: Correct, low urine volume due to inadequate fluid intake can cause nephrolithiasis in 10–50% of cases.
D) 15–30%: Incorrect, this is the prevalence for Idiopathic low urine pH.
Memory Tool: “Low urine? High chance! 10–50%” to remember the prevalence range.
Reference Citation: Modified from Pearle MS, Pak CY, in “International yearbook of nephrology,” 1996, Table 91.2, paragraph 1.
Rationale: Emphasizing hydration may prevent future episodes.
Question 1: A patient is found to have struvite stones and you suspect the presence of a urease-producing bacteria. Which of the following gram-negative bacteria is most likely (>90% of isolates) to produce urease?
Options:
A. Haemophilus influenzae
B. Proteus mirabilis
C. Pseudomonas aeruginosa
D. Klebsiella pneumoniae
Correct Answer:
B. Proteus mirabilis
Explanation:
A. Haemophilus influenzae: Occasional urease-producer (5%-30% of isolates).
B. Proteus mirabilis: Usually produces urease (>90% of isolates).
C. Pseudomonas aeruginosa: Occasional urease-producer (5%-30% of isolates).
D. Klebsiella pneumoniae: Occasional urease-producer (5%-30% of isolates).
Memory Tool:
Remember the phrase “Proteus Mira-Bliss” to recall that Proteus mirabilis is blissfully (>90%) urease-positive.
Reference Citation:
Gleeson MJ, Griffith DP: Infection stones. In Resnick MI, Pak CYC, editors: Urolithiasis: a medical and surgical reference, Philadelphia, 1990, Saunders, p 115. (Table 91.3)
Rationale:
Knowing the urease-producing capacity of bacteria is essential for accurate diagnosis and treatment of struvite stones.
Question 2: Which gram-positive organism is LEAST likely to produce urease based on the given table?
Options:
A. Corynebacterium ulcerans
B. Bacillus species
C. Peptococcus asaccharolyticus
D. Staphylococcus aureus
Correct Answer:
D. Staphylococcus aureus
Explanation:
A. Corynebacterium ulcerans: Listed as a urease-producer.
B. Bacillus species: Listed as a urease-producer.
C. Peptococcus asaccharolyticus: Listed as a urease-producer.
D. Staphylococcus aureus: Listed as a urease-producer, but unlike the others, it is well-known to produce urease occasionally rather than usually.
Memory Tool:
Remember “Staph Aure-LEAST” to remember that Staphylococcus aureus is least likely among the options to produce urease.
Reference Citation:
Gleeson MJ, Griffith DP: Infection stones. In Resnick MI, Pak CYC, editors: Urolithiasis: a medical and surgical reference, Philadelphia, 1990, Saunders, p 115. (Table 91.3)
Rationale:
Identifying organisms least likely to produce urease can help in differential diagnosis and in directing antibiotic therapy.
Question 3: A patient presents with suspected infection stones, and Mycoplasma is being considered as a causative agent. Which Mycoplasma species should be suspected as a urease-producer?
Options:
A. T-strain Mycoplasma
B. Mycoplasma genitalium
C. Ureaplasma urealyticum
D. Mycoplasma pneumoniae
Correct Answer:
C. Ureaplasma urealyticum
Explanation:
A. T-strain Mycoplasma: Listed as a urease-producer, but it’s not typically associated with urological issues.
B. Mycoplasma genitalium: Not listed in the table.
C. Ureaplasma urealyticum: Specifically listed as a Mycoplasma species that usually produces urease.
D. Mycoplasma pneumoniae: Not listed in the table.
Memory Tool:
“Urea-plasma, Urea-lytic!”—Ureaplasma urealyticum is the Mycoplasma species concerned with urea breakdown.
Reference Citation:
Gleeson MJ, Griffith DP: Infection stones. In Resnick MI, Pak CYC, editors: Urolithiasis: a medical and surgical reference, Philadelphia, 1990, Saunders, p 115. (Table 91.3)
Rationale:
Differentiating between Mycoplasma species is vital for accurate diagnosis and treatment of infection stones.
uestion 4: You suspect an infection stone caused by yeast in a patient. Which of the following yeasts is NOT listed as a urease-producer?
Options:
A. Cryptococcus
B. Candida albicans
C. Rhodotorula
D. Sporobolomyces
orrect Answer:
B. Candida albicans
Explanation:
A. Cryptococcus: Listed as a urease-producing yeast.
B. Candida albicans: Not listed as a urease-producer in the table; Candida humicola is listed instead.
C. Rhodotorula: Listed as a urease-producing yeast.
D. Sporobolomyces: Listed as a urease-producing yeast.
Memory Tool:
Remember “Candida Albi-GONE” to help remember that Candida albicans is gone from the list of urease-producers.
Reference Citation:
Gleeson MJ, Griffith DP: Infection stones. In Resnick MI, Pak CYC, editors: Urolithiasis: a medical and surgical reference, Philadelphia, 1990, Saunders, p 115. (Table 91.3)
Rationale:
Knowing which yeasts don’t produce urease could guide treatment choices and further diagnostics.
Clinical Vignette:
You are consulting for a patient who reports having sharp, intermittent pain in the lower abdomen. Upon microscopic examination of a collected urinary calculus, you observe an “envelope, tetrahedral” appearance.
Multiple-Choice Options:
A) Calcium oxalate monohydrate
B) Calcium oxalate dihydrate
C) Calcium phosphate-apatite
D) Uric acid
Correct Answer:
B) Calcium oxalate dihydrate
In-Depth Explanation:
A) Calcium oxalate monohydrate: Incorrect. This type of urinary calculus usually has an “hourglass” appearance under the microscope.
B) Calcium oxalate dihydrate: Correct. The “envelope, tetrahedral” microscopic appearance is characteristic of calcium oxalate dihydrate crystals.
C) Calcium phosphate-apatite: Incorrect. This typically appears “amorphous” under microscopic examination.
D) Uric acid: Incorrect. These crystals usually appear as “amorphous shards, plates” microscopically.
Clinical Vignette:
A patient has chronic kidney issues and upon examination, you observe urinary calculi with a needle-shaped appearance.
Multiple-Choice Options:
A) Brushite
B) Cystine
C) Magnesium ammonium phosphate (struvite)
D) Uric acid
Correct Answer:
A) Brushite
In-Depth Explanation:
A) Brushite: Correct. The “needle-shaped” appearance is characteristic of Brushite calculi.
B) Cystine: Incorrect. Cystine calculi would have a “hexagonal” appearance.
C) Magnesium ammonium phosphate (struvite): Incorrect. These typically appear as “rectangular, coffin-lid” shapes.
D) Uric acid: Incorrect. Uric acid crystals appear as “amorphous shards, plates.”
Memory Tool:
“Brushite is like a needle in a haystack” can help you remember the needle-shaped appearance of Brushite.
Reference Citation:
Table 92.2: Microscopic Appearance of Common Urinary Calculi
Rationale for Question Importance:
Recognizing the microscopic appearance of various calculi allows for better treatment planning, especially for patients with chronic kidney issues.
Clinical Vignette:
A young patient presents with a history of recurrent urinary tract stones. A microscopic evaluation reveals a hexagonal-shaped urinary calculus.
Multiple-Choice Options:
A) Magnesium ammonium phosphate (struvite)
B) Brushite
C) Cystine
D) Uric acid
Correct Answer:
C) Cystine
In-Depth Explanation:
A) Magnesium ammonium phosphate (struvite): Incorrect. Struvite usually appears as “rectangular, coffin-lid” shapes.
B) Brushite: Incorrect. Brushite calculi are “needle-shaped.”
C) Cystine: Correct. A “hexagonal” shape is characteristic of Cystine calculi.
D) Uric acid: Incorrect. These crystals usually appear as “amorphous shards, plates.”
Memory Tool:
Remember, “Cystine is Six-sided” to associate the hexagonal shape with Cystine.
Reference Citation:
Table 92.2: Microscopic Appearance of Common Urinary Calculi
Rationale for Question Importance:
Identifying Cystine calculi is especially important in younger patients with recurrent urinary tract stones, as it may indicate a genetic predisposition requiring specialized treatment.
Clinical Vignette:
A 40-year-old woman presents with fever and chills in addition to urinary symptoms. Microscopic examination of her urinary calculus shows a “rectangular, coffin-lid” shape.
Multiple-Choice Options:
A) Calcium phosphate-apatite
B) Magnesium ammonium phosphate (struvite)
C) Calcium oxalate monohydrate
D) Uric acid
Correct Answer:
B) Magnesium ammonium phosphate (struvite)
In-Depth Explanation:
A) Calcium phosphate-apatite: Incorrect. Typically appears as “amorphous.”
B) Magnesium ammonium phosphate (struvite): Correct. Struvite calculi are usually “rectangular, coffin-lid” in shape.
C) Calcium oxalate monohydrate: Incorrect. This type generally has an “hourglass” appearance.
D) Uric acid: Incorrect. These usually appear as “amorphous shards, plates.”
Memory Tool:
Think “Struvite is your coffin-lid ticket to UTIs” to remember its rectangular, coffin-lid shape and its association with urinary tract infections.
Reference Citation:
Table 92.2: Microscopic Appearance of Common Urinary Calculi
Rationale for Question Importance:
Struvite stones are often associated with infections, and identifying them can guide the choice of antibiotics alongside stone management.
Clinical Vignette:
You are treating an elderly male patient who has been experiencing flank pain. Microscopic evaluation of his urinary calculus shows “amorphous shards, plates.”
Multiple-Choice Options:
A) Brushite
B) Cystine
C) Calcium phosphate-apatite
D) Uric acid
Correct Answer:
D) Uric acid
In-Depth Explanation:
A) Brushite: Incorrect. Brushite calculi would show a “needle-shaped” appearance.
B) Cystine: Incorrect. These are usually “hexagonal” in shape.
C) Calcium phosphate-apatite: Incorrect. This type appears “amorphous,” but not as shards or plates.
D) Uric acid: Correct. Uric acid calculi present as “amorphous shards, plates.”
Memory Tool:
“Uric Acid is Unpredictable Shards” can help you remember the unique appearance of uric acid calculi.
Reference Citation:
Table 92.2: Microscopic Appearance of Common Urinary Calculi
Rationale for Question Importance:
Knowing the characteristic appearance of uric acid stones may point to specific dietary factors or metabolic issues, aiding in targeted treatment.
Clinical Vignette:
A 30-year-old male is experiencing recurring urinary tract infections. Upon microscopic evaluation, you notice the urinary calculus appears “amorphous.”
Multiple-Choice Options:
A) Calcium phosphate-apatite
B) Magnesium ammonium phosphate (struvite)
C) Calcium oxalate monohydrate
D) Uric acid
Correct Answer:
A) Calcium phosphate-apatite
In-Depth Explanation:
A) Calcium phosphate-apatite: Correct. The “amorphous” appearance is characteristic of Calcium phosphate-apatite calculi.
B) Magnesium ammonium phosphate (struvite): Incorrect. These usually have a “rectangular, coffin-lid” appearance.
C) Calcium oxalate monohydrate: Incorrect. These appear as “hourglass.”
D) Uric acid: Incorrect. These appear as “amorphous shards, plates.”
Memory Tool:
“Phosphate is Formless” can help you remember the amorphous nature of Calcium phosphate-apatite stones.
Reference Citation:
Table 92.2: Microscopic Appearance of Common Urinary Calculi
Rationale for Question Importance:
Understanding the amorphous nature of Calcium phosphate-apatite stones may prompt further evaluation for underlying causes, especially in younger patients with recurrent infections.
Question 1:
A 45-year-old male presents with recurrent calcium oxalate stones. After a thorough evaluation, you decide to start him on a thiazide diuretic. Which of the following doses is correct for Hydrochlorothiazide for this indication?
A. 50 mg PO daily
B. 25 mg PO bid
C. 10 mg PO daily
D. 100 mg PO daily
Correct Answer: B
Explanation:
A: 50 mg daily is not the recommended dosage for Hydrochlorothiazide for urinary calculi. It’s an incorrect dosage.
B: 25 mg PO bid is the correct dosage as per the guidelines provided in Table 92.4.
C: 10 mg daily is lower than the recommended dosage.
D: 100 mg PO daily is excessive and not recommended.
Memory Tool: “25 Twice” helps you remember the dose and frequency.
Reference Citation: Table 92.4
Rationale: Knowing the correct dosage is crucial for effective treatment and minimizing side effects.